Silo x20 series railheads are the perfect replacements for halogen MR16s as they offer lower wattage with superior lumen output, over 10 times the rated lifespan, less maintenance, no projected heat, and beam shift technology. All silo x20 series luminaries are equipped with beam shift technology, allowing continuous in-field modification of beam angle from spot to flood. For use with the 120v Wac Lighting flex rail.